could you try a simple print for me ?
just the multi color calibration print or so but wiht the following
first print no tower, so it only purge but on minimum value’s like 70 - 40 or so
second print only with purge tower ( same value’s preffered )
and last print with both of them , not sure if it double the waste amount or splits the waste amount between tower and back
also i stil feel that those purge value’s are way more then needed , on my pallet i used way lower value’s with out color bleeding
there is one more thing you could try , but not sure if bambu slicer got that
prusaslicer got a option to only make a waste tower when changing colors , this will prevent printing a tower unless it changes the filmanet , but can cause collissions ofcourse
as it seems the front is already taken with the purge line so you could place the tower there as it then got the full widht of the purge line to lower with out causing collisions, this should decrease the waste by a lot
this are only a few idea’s 